Potassium Acid Phthalate Crystals Research Articles

Effect of shock wave on surface morphology and optical properties of acid phthalate based single crystals

Recent literature reports mentioned that the effect of shock wave on single crystals and its effect on various physical and chemical properties. In the current article, the shock wave with constant Mach number 1.7 was generated by table top shock tube to study its effects on optical and surface morphology properties of Potassium Acid Phthalate (KAP) and Sodium Acid Phthalate (NaAP) single crystals respectively. Optically transparent semi-organic single crystals of KAP and NaAP were grown using slow evaporation solution technique (SEST). A systematic investigation was carried out to examine the influence of shock waves on acid phthalate based single crystals. The optical properties of harvested crystals were scrutinized using UV–Visible and photoluminescence (PL) spectroscopy. The surface morphology analysis was examined by optical microscope. On the interaction of shock wave, the transmittance for both the crystals increased for 1st shock wave and then decreased for its higher shock numbers. There were no major changes observed in optical band gap for pre and post shock wave loaded single crystals. The modification on the surface of single crystal, study of defects concentration and crystalline perfection of the virgin and shock wave loaded samples were confirmed by PL and surface morphology studies respectively.

Band tunable X‐ray flat crystal spectrometer for laser‐produced plasma spectroscopy measurements

AbstractAn updated design of a band‐tunable flat crystal spectrometer is presented. The new configuration contributes to a broad spectral coverage with greater resolving power, a strong rejection of hard X‐ray backgrounds, and decreased sensitivity to source broadening for an extended source. To verify the performance of the spectrometer, spectral lines were measured using a potassium acid phthalate crystal for highly ionized species of aluminum or silicon, and the results were compared by measuring H‐ and He‐like Al and Si lines by rotating the crystal to selected Bragg angles, at the Shenguang II laser facility. The observed energy‐coverage range is consistent with the theoretical predictions, as well as with the measured spectral resolution of ~300.

Lateral deformations of a crystal of potassium acid phthalate in an external electric field

The anisotropy of deformations in potassium acid phthalate crystals arising under the action of an external electric field up to 1 kV mm−1 applied along the [001] polar axis was studied using X-ray diffraction methods at room temperature. Electrical conductivity was measured and rocking curves for reflections 400, 070 and 004 were obtained by time-resolved X-ray diffractometry in Laue and Bragg geometries. Two saturation processes were observed from the time dependences of the electrical conductivity. A shift in the diffraction peaks and a change in their intensity were found, which indicated a deformation of the crystal structure. Rapid piezoelectric deformation and reversible relaxation-like deformation, kinetically similar to the electrical conductivity of a crystal, were revealed. The deformation depended on the polarity and strength of the applied field. The deformation was more noticeable in the [100] direction and was practically absent in the [001] direction of the applied field. X-ray diffraction analysis revealed a disordered arrangement of potassium atoms, i.e. additional positions and vacancies. The heights of potential barriers between the positions of K+ ions and the paths of their possible migration in the crystal structure of potassium acid phthalate were determined. The data obtained by time-resolved X-ray diffractometry and X-ray structure analysis, along with additional electrophysical measurements, allow the conclusion that the migration of charge carriers (potassium cations) leads to lateral deformation of the crystal structure of potassium phthalate in an external electric field.

Recent enhancements in the performance of the Orion high-resolution x-ray spectrometers.

During the past few years, the Orion high-resolution x-ray spectrometers have been successful tools for measuring x-ray spectra from plasmas generated in the Orion laser facility. Duplicate spectrometers also operate successfully at the Livermore EBIT-I and SuperEBIT electron beam ion traps for measuring x-ray polarization. We have recently implemented very high-quality, optically bonded, spherically bent quartz crystals to remove the structure in the x-ray image that had been observed in earlier measurements. The structure had been caused by focusing defects and limited the accuracy of our measurements. We present before and after images that show a drastic improvement. We, furthermore, have implemented a spherically bent potassium acid phthalate (KAP) crystal on one of our spectrometers. The KAP crystal was prepared in a similar fashion, and we present measurements of the N Ly-β and Ne Lyβ lines taken in first- and second-order reflections at 600 and 1200eV, respectively. These measurements confirm that KAP crystals can be produced at a quality suitable for extending the spectral coverage to wavelengths longer than those accessible by different quartz crystals, especially those that cover the astrophysically important lines of iron.

Comparative analysis of pristine and Cd2+ influenced potassium acid phthalate single crystal for photonic device applications

A very first attempt has been made to improve the overall performance of potassium acid phthalate (KAP) crystal using Cd2+ ion, hence pristine and Cd2+ influenced KAP (Cd-KAP) crystal has been grown at 35 °C by slow solvent evaporation method. The comparative approach of analysis has been adopted to explore the structural, optical and electrical properties of Cd-KAP crystal. The single crystal X-ray diffraction analysis has been employed to determine the structural parameters of grown crystal. The element detection of Cd-KAP crystal has been performed by means of energy dispersive spectroscopic technique. The enhancing impact of Cd2+ on optical transmittance of KAP crystal has been examined using the UV–vis spectral analysis. The 2nd and 3rd order nonlinear optical features of Cd-KAP crystal has been assessed by employing Kurtz-Perry test and Z-scan analysis respectively. The second harmonic generation efficiency of Cd-KAP crystal is found higher than KDP and KAP crystal. He-Ne laser assisted Z-scan analysis has been imposed to examine and evaluate the third order nonlinear optical properties (n2, β, χ3) of Cd-KAP crystal. The dielectric constant and dielectric loss of pure and Cd-KAP crystal has been comparatively evaluated at different temperatures ranging from room temperature to 90 °C.

Linear and Nonlinear Optical Constants of Potassium Acid Phthalate crystal

Single crystals of potassium hydrogen phthalate (KAP) are grown by solution growth technique. Linear optical constants are evaluated from UV/VIS/NIR spectrum. The Z scan technique is used to elucidate the third order nonlinearity in the material. The results indicate that the compound exhibits reverse saturable absorption (RSA) and self-defocusing performance. The second harmonic generation (SHG) efficiency of the crystal evaluated by Kurtz and Perry technique is compared with that of the standard KDP crystal. Attempt is made to correlate the SHG efficiency with the crystalline perfection in the material. Full Text: PDF ReferencesMiniewicz.A, Barkiewics.S, "On the electro‐optic properties of single crystals of sodium, potassium and rubidium acid phthalates", Adv.Mat.Opt.Elect,2,157(1993). CrossRef Comeretto.D, Rosy.L, "Optical properties of potassium acid phthalate", J.Mat.Res, 12, 1262(1997). CrossRef Krajewski.T, Breczewski.T, "Dielectric and pyroelectric properties of TGS crystals doped with nitroaniline molecules", Ferroelectrics, 25, 547 (1980). CrossRef N. Kejalakshmy, K. Srinivasan, "Growth, optical and electro-optical characterisations of potassium hydrogen phthalate crystals doped with Fe3+ and Cr3+ ions", Opt. Mater. 27,389–394A, (2004). [5] CrossRef Ester. G.R, Price.R, Halfpenny. P.J, "An atomic force microscopic investigation of surface degradation of potassium hydrogen phthalate (KAP) crystals caused by removal from solution", J.Cryst.Growth, 182, 95(1998). CrossRef Hiroyuki Toda, Carl M. Verber "Simple technique to reveal a slow nonlinear mechanism in a z-scanlike n2 measurement", Opt. Lett. 17(19) 1379(1992). CrossRef K.J. Arun, S.Jayalekshmi, "Investigations on the nonlinear optical properties of glycinium oxalate single crystals", Optoelectron. Lett. 7(2), 136, (2011). CrossRef K.J.Arun, S.Jayalekshmi, "Third order nonlinear optical constants of L-alaninium oxalate", Phot. Lett. Poland 7(3), 81-83 (2015) CrossRef

Effect of cobalt (Co2+) concentration on structural, optical, thermal and mechanical properties of potassium acid phthalate (KAP) crystals

Single crystals of pure and Co2+ (0.2, 0.4 and 0.6 mol%) doped KAP crystals were grown by low temperature slow evaporation method. The grown crystals were subjected to various characterization techniques such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV–visible spectroscopy and Second Harmonic Generation studies. The XRD profile confirms that Co2+ ions incorporated into the KAP crystal lattice. The existence of functional groups in the grown crystals have been studied by FTIR analysis. Optical transmission is decreased when doping Co2+ concentration increase. After melting point, no decomposition is found in the pure crystal. Vickers micro hardness studies revealed that the doped crystals possess very high hardness values. The dielectric constant, dielectric loss and thermal stability values have been measured as a function of frequency and temperature respectively for the doped crystals.

Effect of alkali halides on the growth, morphology, spectral, optical, thermal and nonlinear optical properties of potassium acid phthalate crystals for frequency conversion applications

Slow Evaporation Solution Growth Technique was employed for the growth of transparent alkali halide doped potassium acid phthalate crystals. The structure of the crystals was confirmed by single crystal X-ray diffraction. Powder X-ray diffraction analysis confirms the absence of multiple phases in the crystal and it suggests that the crystalline nature of the samples remain unaltered even after the addition of the dopants. Linear and nonlinear optical properties were examined by UV–Visible spectral analysis and Kurtz-Perry method of NLO testing respectively. The results of NLO test evokes that alkali halide doped crystals are phase matchable. The thermal stability of the grown crystals was assessed by TG/DTA analysis. The surface morphology of the grown crystals was studied by SEM analysis. EDX analysis provides the statistical information of the elemental composition of the samples from which the incorporation of the dopants is confirmed. In general the obtained results ensure that the title materials are desirable candidates for NLO applications.

Measurement and models of bent KAP(001) crystal integrated reflectivity and resolution (invited).

The Advanced Light Source beamline-9.3.1 x-rays are used to calibrate the rocking curve of bent potassium acid phthalate (KAP) crystals in the 2.3-4.5 keV photon-energy range. Crystals are bent on a cylindrically convex substrate with a radius of curvature ranging from 2 to 9 in. and also including the flat case to observe the effect of bending on the KAP spectrometric properties. As the bending radius increases, the crystal reflectivity converges to the mosaic crystal response. The X-ray Oriented Programs (xop) multi-lamellar model of bent crystals is used to model the rocking curve of these crystals and the calibration data confirm that a single model is adequate to reproduce simultaneously all measured integrated reflectivities and rocking-curve FWHM for multiple radii of curvature in both 1st and 2nd order of diffraction.

Polaron conductivity mechanism in potassium acid phthalate crystal: AC-conductivity investigation

The complex dielectric constant, , of potassium acid phthalate monocrystal (KAP) was investigated over the broad frequency and temperature range. While the imaginary part of dielectric constant ε′′(ν) increases rapidly with increasing temperature in the studied temperature range, the real part of dielectric constant ε′(ν) increases only at high temperatures; there is almost no change of ε′(ν) below 200 K. Both values of ε′ and ε′′ are frequency dependent; the values increase with decreasing frequencies. At temperatures below 450 K the ac electrical conductivity and dielectric constant follow simultaneously the universal dielectric response (UDR). The analysis of the temperature dependence of the UDR parameter s in terms of the theoretical model for small polarons revealed that this mechanism governs the charge transport in KAP crystal in the studied temperature range.

Investigations on the growth, optical, thermal, dielectric, and laser damage threshold properties of crystal violet dye-doped potassium acid phthalate single crystal

Influence of crystal violet dye with different concentration on potassium acid phthalate single crystal grown by conventional method has been studied. No change has been observed in the structure, whereas changes have been observed in the external morphology of the crystal when the dyes are incorporated in the crystal lattice. Thermogravimetric and differential thermal analyses show the onset decomposition temperatures to be at 302, 285, 284, and 285 °C for pure, 0.1, 0.3, and 0.5 mol% crystal violet-doped potassium acid phthalate crystals, respectively. The dielectric measurement was carried out on the grown crystals as a function of frequency at various temperatures. In addition, strong luminescent emission bands at 638, 648, and 640 nm were observed in which the relative intensity was found to be reversed as a result of doping concentration. The laser damage threshold value significantly increased for dye-doped crystal in comparison with pure crystal which may make it suitable for the solid-state dye laser applications.

Synthesis, linear optical, non-linear optical, thermal and mechanical characterizations of dye-doped semi-organic NLO crystals

Organic laser dyes Coumarin 485, Coumarin 540 and Rhodamine 590 Chloride were used to dope potassium acid phthalate crystals (KAP). Dye-doped KAP crystals with different dye concentrations such as 0.01 mM, 0.03 mM, 0.05 mM, 0.07 mM and 0.09 mM (in the KAP growth solution) were grown. The linear optical, non-linear optical, mechanical and thermal characterizations of dye-doped KAP crystals were studied and compared to understand the effect of dye and dye concentration on the KAP crystal. Absorption and emission studies of KAP and dye-doped KAP single crystals indicated the inclusion of the dye into the KAP crystal lattice. The effect of dye and its concentration on the SHG efficiency of the KAP crystal was studied using the Kurtz and Perry powder technique. It was observed that the absorption maximum wavelength and concentration of the dye used for doping the KAP single crystal decided the SHG efficiency of the dye-doped KAP single crystals. The mechanical hardness of the dye-doped and undoped (pure) KAP single crystals were studied using the Vickner’s microhardness test. It was observed that doping the KAP crystals with the laser dyes changed them from softer material to harder material. Etching studies showed an improvement in the optical quality of the KAP crystal after doping with laser dyes.

Synthesis, Growth and Characterization of Ni2+ incorporated Potassium Acid Phthalate crystal: A Potential material for NLO applications

Undoped and Nickel nitrate (Ni2+) doped Potassium acid phthalate (KAP C8H5KO4) single crystals were grown by cost effective Slow Evaporation Solution Growth. The grown crystals were subjected to various characterization techniques. The structural and lattice parameters were analyzed by single crystal X-ray diffraction. The spectral properties were assessed by FTIR spectral analysis. Optical characters were analyzed by UV-Vis spectral studies. Mechanical properties of the doped and undoped crystals were evaluated by Vicker's Microhardness study. Thermal stability of the sample was assessed by TG/DTA analysis. EDX analysis confirms the incorporation of metal ion into the crystal lattice of the title compound. SHG studies confirm that Ni2+ doped KAP crystal is a potential candidate for NLO applications.

Effect of amino acid dopants on the spectral, optical, mechanical and thermal properties of potassium acid phthalate crystals for possible optoelectronic and frequency doubling applications

Abstract Undoped and amino acid ( l -Arginine and l -Valine) doped KAP crystals were grown by slow evaporation solution growth technique. The changes in the structural, spectral, optical, mechanical and thermal properties were observed. The sharp prominent peaks in the indexed powder XRD pattern confirms the crystalline nature of the sample. Optical studies reveal that the crystal is transparent in the entire visible light region. Thermal stability was checked by TG/DTA analysis. The mechanical stability was evaluated from Vicker’s microhardness test. The SHG efficiency for the title materials was tested with different particle sizes by the Kurtz and Perry powder method, which established the existence of phase matching.

Growth, structural, thermal and optical properties of Mg2+ -Co2+ doped potassium acid phthalate crystals

Single crystals of pure potassium acid phthalate (KAP) and magnesium-cobalt (Mg2+-Co2+) co-doped potassium acid phthalate crystals were grown by an isothermal evaporation method. Optically transparent and coloured KAP single crystals were grown by doping divalent bimetallic impurities. Enhancement of the metastable zonewidth was achieved by the addition of co-doped bimetallic impurities in KAP solution. It is anticipated that these larger cations play a vital role in the growth mechanism and it favours to reduce the formation of secondary nucleation by positioning the doped metal ions into the interstitial sites. The XRD results confirm that the incorporation of bimetallic ions into the KAP crystal lattice. The optical transmission is found to decrease in Mg-Co doped crystals compared to that of pure KAP. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17557 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 2, 165-172, 2013

Dispersions in crystal nucleation and growth rates: Implications of fluctuation in supersaturation

Crystallization is one of the most commonly used and relatively well explored techniques in industries. Yet there are beleaguering issues towards fundamental understanding of this process. One of the curious observations is the appearance of unavoidable dispersions in nucleation and growth rates of crystalline materials grown under homogenous bulk conditions. These dispersions can contribute significantly towards polydispersity in crystalline products. The classical models such as Gibbs critical nucleation theory and Burton–Cabrera–Frank growth models primarily relate nucleation and growth to supersaturation. Therefore, the dispersions in nucleation and growth rates can be related to the local fluctuations in supersaturation. These local fluctuations are driven by the Brownian motion of solute molecules which affects the local concentration and temperature and hence supersaturation. This article presents a stochastic model to describe fluctuations in supersaturation and thereby dispersions in crystalline materials. The stochastic model is derived from the framework of density and temperature fluctuations. The resulting dispersions in size and shape of nuclei are obtained by multi-dimensional maximization of Gibbs free energy in morphology domain of potassium acid phthalate. The model predictions are validated with the experimental measurements of growth rate dispersions in potassium acid phthalate crystals. The proposed framework provides the first ab initio predictions for the observed dispersions in crystallization processes.

Effect of trivalent metal ion impurities (Al3+, Cr3+ and Fe3+) on the growth, structural and physical properties of potassium acid phthalate (KAP) crystals

Trivalent metal ion (Al, Cr, Fe) doped potassium hydrogen phthalate (KAP) crystals have been grown from aqueous solution at room temperature. Powder XRD and ICP-OES studies confirmed the metal ion doping into KAP crystals. The presence of functional groups in the crystal has been observed by FTIR analysis. Optical transmission studies were carried out by allowing the UV-NIR ray of wavelength between 190 and 1000nm to pass through the (010) face of the grown KAP crystals. Dielectric constant value of Fe-doped KAP at 100Hz was found to be significantly higher than that of undoped and Cr and Al-doped KAP. TG-DTA studies show the decomposition temperatures to be 255, 270, 258 and 287°C for pure, Al3+, Cr3+ and Fe3+ doped KAP crystals respectively. Microhardness studies reveal that the Cr3+ and Fe3+ doped crystals have higher hardness values than that of undoped and Al-doped KAP. The grown crystals were also subjected to second harmonic generation (SHG) efficiency tests.

Proton Transfer and Photoluminescence Intermittency of Single Emitters in Dyed Crystals

The role of proton transfer in the photoluminescence intermittency (PI) of single molecules of violamine R (VR) overgrown in potassium acid phthalate (KAP) crystals is evaluated in comparisons of protonated (KAP) and deuterated (DKAP) mixed crystals between 23 and 60 °C. The PI is analyzed by the construction of cumulative distribution functions that are statistically compared. We find that the on- and off-interval duration distributions change with isotopic substitution consistent with proton transfer contributing to the PI of VR. The on- and off-interval duration distributions have distinct temperature dependencies consistent with different mechanisms for dark state production and decay. Additional evidence for proton-transfer is provided by distributions of single molecule emission-energy maxima that reflect emission from protonated and deprotonated VR. A mechanism for the PI of KAP is presented, where the dark state is assigned to formation of the colorless, leuco form of VR, formed by proton transfer from VR to the KAP lattice, and decay of the dark state involves ring-opening promoted by proton transfer from KAP to VR. The distributed kinetics for dark-state production and decay are modeled using a log-normal distribution for the PI data in preference to a power-law previously assumed. A discussion of the log-normal distribution with regards to PI and proton transfer is presented.

Beyond power laws: A new approach for analyzing single molecule photoluminescence intermittency

The photoluminescence intermittency (PI) exhibited by single emitters has been studied for over a decade. To date, the vast majority of PI analyses involve parsing the data into emissive and non-emissive events, constructing histograms of event durations, and fitting these histograms to either exponential or power law probability distributions functions (PDFs). Here, a new method for analyzing PI data is presented where the data are used directly to construct a cumulative distribution function (CDF), and maximum-likelihood estimation techniques are used to determine the best fit of a model PDF to the CDF. Statistical tests are then employed to quantitatively evaluate the hypothesis that the CDF (data) is represented by the model PDF. The analysis method is outlined and applied to PI exhibited by single CdSe∕CdS core-shell nanocrystals and the organic chromophore violamine R isolated in single crystals of potassium-acid phthalate. Contrary to previous studies, the analysis presented here demonstrates that the PI exhibited by these systems is not described by a power law. The analysis developed here is also used to quantify heterogeneity within PI data obtained from a collection of CdSe/CdS nanocrytals, and for the determination of statistically significant changes in PI accompanying perturbation of the emitter. In summary, the analysis methodology presented here provides a more statistically robust approach for analyzing PI data.

Effect of amino acid additives on the growth and physical properties of potassium acid phthalate (KAP) crystals

Single crystals of potassium acid phthalate (KAP) have been grown from aqueous solution by slow evaporation technique by adding l-alanine (LA), glycine (Gly) and l-tyrosine (LT) as additives. Powder X-ray diffraction studies confirmed the phase formation and amino acids doping into KAP crystals. The optical absorption studies reveal that the LA doped crystals possess less absorption of visible ray than the pristine, Gly and LT doped KAP crystals. Optical transmission is found to be low in LT doped KAP than in all the other crystals. TG–DTA studies show the decomposition temperatures to be 255°C, 232°C, 258°C and 264°C for pure, LA, Gly and LT doped KAP crystals respectively. SHG efficiency of LA doped KAP crystal was found to be 1.1 times (31mV for KDP and 34mV for LA doped KAP) that of potassium dihydrogen phosphate (KDP) crystal. This is much higher when compared to that of undoped KAP crystal (12mV). The grown crystals were also subjected to FTIR, microhardness and dielectric studies.